The Sunday Express reported that the duchess donated her hair while at the hairdresser, and it was passed along anonymously.

Helen Creese, a spokeswoman for the charity, told Metro: “It’s a complete surprise. Obviously we’re all absolutely delighted that she donated her hair, and we’re very grateful as well, just as we’re grateful to everyone who chooses to support the charity in this way, and so many people do.”

Kate Middleton gave her hair to the Little Princess Trust. (Photo: Getty Images)

“We’re assuming that she might have sent the donation anonymously.”

Usually when people donate their hair to the charity, they send it with their name and email address attached, so the Little Princess Trust can thank them properly.

However, Ms. Creese pointed out they do occasionally receive anonymous donations, and said: “It’s such a selfless act anyway to donate your hair to help a sick child or young adult.”

The duchess isn’t the first high-profile donation the charity has received. In 2016, One Direction’s Harry Styles chopped off his hair to be made into a wig.

And Jessie J famously shaved her hair back in 2013 for the same charity.

Shailene Woodley, who played cancer patient Hazel Grace Lancaster in The Fault in Our Stars, shaved and donated her hair to Children With Hair Loss, and Amanda Seyfried donated hers to Locks for Love.